This invention relates to a universal ear plug which fits any size ear and provides better performance and a greater noise reduction ratio.
Most molded earplugs which are available today are made in a number of sizes to fit different sized ears.
For example, Veneklasen, U.S. Pat. No. 2,393,005 discloses an ear plug with an outwardly extending flange at the tip of the plug which is inserted into the ear. The primary seal is made by a thin portion of a flexible tubular body, which seals against the outer edge of the ear canal. When the finger is pushed against the outer edge of the plug during insertion, the tubular body collapses causing the tip of the plug to enter the ear canal at an obtrusive angle. The tip of the plug protrudes relatively far into the ear canal, causing discomfort during extended periods of wear. Veneklasen's plug is made in a variety of sizes and must be inserted into the ear at the proper angle and position. It is often a laborious task to achieve a proper fit.
Another earplug is manufactured by Mine Safety Appliances Company, Pittsburgh, Pa. under the trademark "ACCU-FIT". The ACCU-Fit plug is comprised of a solid body portion with three outwardly extending flanges spaced lengthwise along the body. The first flange is located at the tip of the plug. This flange is the same as the flange used on Veneklasen's plug. The second flange is of greater diameter and is situated around the center of the body. The last flange is at the end of the plug and has the largest diameter. When inserted, one or more of the flanges will engage the ear canal depending on the ear size and the length of insertion. When inserted into a large ear, the plug protrudes quite far into the ear canal. This can result in discomfort during extended periods of wear. The ACCU-FIT plug has an extension of the central body portion which acts as the inserter. Since the plug is pushed from the center, the body sometimes distorts and the plug enters the ear canal at an angle. This can result in discomfort and diminished noise reduction.
Ear plugs using the post or body of the plug as the inserter, being of a soft material, also have a tendency to buckle or expand in the middle when pushed from the back end, as the front end resists being pushed into the ear. When the pushing stops, the expanded material relaxes tending to move the plug back out of the ear. This can cause improper sealing and diminished noise reduction.